BESS Workgroup A. Sajassi, Ed. INTERNET-DRAFT A. Banerjee Intended Status: Standards Track S. Thoria D. Carrel B. Weis Cisco Expires: May 20, 2019 October 20, 2018 Secure EVPN draft-sajassi-bess-secure-evpn-00 Abstract The applications of EVPN-based solutions ([RFC7432] and [RFC8365]) have become pervasive in Data Center, Service Provider, and Enterprise segments. It is being used for fabric overlays and inter- site connectivity in the Data Center market segment, for Layer-2, Layer-3, and IRB VPN services in the Service Provider market segment, and for fabric overlay and WAN connectivity in Enterprise networks. For Data Center and Enterprise applications, there is a need to provide inter-site and WAN connectivity over public Internet in a secured manner with same level of privacy, integrity, and authentication for tenant's traffic as IPsec tunneling using IKEv2. This document presents a solution where BGP point-to-multipoint signaling is leveraged for key and policy exchange among PE devices to create private pair-wise IPsec Security Associations without IKEv2 point-to-point signaling or any other direct peer-to-peer session establishment messages. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." Sajassi et al. Expires May 20, 2019 [Page 1] INTERNET DRAFT Secure EVPN October 20, 2018 The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Tenant's Layer-2 and Layer-3 data & control traffic . . . . 7 2.2 Tenant's Unicast & Multicast Data Protection . . . . . . . . 7 2.3 P2MP Signaling for SA setup and Maintenance . . . . . . . . 7 2.3 Granularity of Security Association Tunnels . . . . . . . . 7 2.4 Support for Policy and DH-Group List . . . . . . . . . . . . 8 3 Solution Description . . . . . . . . . . . . . . . . . . . . . 8 3.1 Distribution of Public Keys and Policies . . . . . . . . . 9 3.1.1 Minimum Set . . . . . . . . . . . . . . . . . . . . . . 9 3.1.2 Single Policy . . . . . . . . . . . . . . . . . . . . . 10 3.1.3 Policy-list & DH-group-list . . . . . . . . . . . . . . 10 3.2 Initial IPsec SAs Generation . . . . . . . . . . . . . . . 11 3.3 Re-Keying . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4 IPsec Databases . . . . . . . . . . . . . . . . . . . . . . 11 4 Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.1 Standard ESP Encapsulation . . . . . . . . . . . . . . . . . 12 4.2 ESP Encapsulation within UDP packet . . . . . . . . . . . . 13 5 BGP Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.1 ESP Notify Sub-TLV . . . . . . . . . . . . . . . . . . . . . 14 5.2 ESP Key Exchange Sub-TLV . . . . . . . . . . . . . . . . . . 15 5.3 ESP Nonce Sub-TLV . . . . . . . . . . . . . . . . . . . . . 15 Sajassi et al. Expires May 20, 2019 [Page 2] INTERNET DRAFT Secure EVPN October 20, 2018 5.3 ESP Proposals Sub-TLV . . . . . . . . . . . . . . . . . . . 16 6 Applicability to other VPN types . . . . . . . . . . . . . . . 17 7 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 8 Security Considerations . . . . . . . . . . . . . . . . . . . . 18 9 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 18 10 References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1 Normative References . . . . . . . . . . . . . . . . . . . 18 10.2 Informative References . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. AC: Attachment Circuit. ARP: Address Resolution Protocol. BD: Broadcast Domain. As per [RFC7432], an EVI consists of a single or multiple BDs. In case of VLAN-bundle and VLAN-based service models (see [RFC7432]), a BD is equivalent to an EVI. In case of VLAN-aware bundle service model, an EVI contains multiple BDs. Also, in this document, BD and subnet are equivalent terms. BD Route Target: refers to the Broadcast Domain assigned Route Target [RFC4364]. In case of VLAN-aware bundle service model, all the BD instances in the MAC-VRF share the same Route Target. BT: Bridge Table. The instantiation of a BD in a MAC-VRF, as per [RFC7432]. DGW: Data Center Gateway. Ethernet A-D route: Ethernet Auto-Discovery (A-D) route, as per [RFC7432]. Ethernet NVO tunnel: refers to Network Virtualization Overlay tunnels with Ethernet payload. Examples of this type of tunnels are VXLAN or GENEVE. EVI: EVPN Instance spanning the NVE/PE devices that are participating on that EVPN, as per [RFC7432]. Sajassi et al. Expires May 20, 2019 [Page 3] INTERNET DRAFT Secure EVPN October 20, 2018 EVPN: Ethernet Virtual Private Networks, as per [RFC7432]. GRE: Generic Routing Encapsulation. GW IP: Gateway IP Address. IPL: IP Prefix Length. IP NVO tunnel: it refers to Network Virtualization Overlay tunnels with IP payload (no MAC header in the payload). IP-VRF: A VPN Routing and Forwarding table for IP routes on an NVE/PE. The IP routes could be populated by EVPN and IP-VPN address families. An IP-VRF is also an instantiation of a layer 3 VPN in an NVE/PE. IRB: Integrated Routing and Bridging interface. It connects an IP-VRF to a BD (or subnet). MAC-VRF: A Virtual Routing and Forwarding table for Media Access Control (MAC) addresses on an NVE/PE, as per [RFC7432]. A MAC-VRF is also an instantiation of an EVI in an NVE/PE. ML: MAC address length. ND: Neighbor Discovery Protocol. NVE: Network Virtualization Edge. GENEVE: Generic Network Virtualization Encapsulation, [GENEVE]. NVO: Network Virtualization Overlays. RT-2: EVPN route type 2, i.e., MAC/IP advertisement route, as defined in [RFC7432]. RT-5: EVPN route type 5, i.e., IP Prefix route. As defined in Section 3 of [EVPN-PREFIX]. SBD: Supplementary Broadcast Domain. A BD that does not have any ACs, only IRB interfaces, and it is used to provide connectivity among all the IP-VRFs of the tenant. The SBD is only required in IP-VRF- to-IP- VRF use-cases (see Section 4.4.). SN: Subnet. TS: Tenant System. Sajassi et al. Expires May 20, 2019 [Page 4] INTERNET DRAFT Secure EVPN October 20, 2018 VA: Virtual Appliance. VNI: Virtual Network Identifier. As in [RFC8365], the term is used as a representation of a 24-bit NVO instance identifier, with the understanding that VNI will refer to a VXLAN Network Identifier in VXLAN, or Virtual Network Identifier in GENEVE, etc. unless it is stated otherwise. VTEP: VXLAN Termination End Point, as in [RFC7348]. VXLAN: Virtual Extensible LAN, as in [RFC7348]. This document also assumes familiarity with the terminology of [RFC7432], [RFC8365] and [RFC7365]. Sajassi et al. Expires May 20, 2019 [Page 5] INTERNET DRAFT Secure EVPN October 20, 2018 1 Introduction The applications of EVPN-based solutions have become pervasive in Data Center, Service Provider, and Enterprise segments. It is being used for fabric overlays and inter-site connectivity in the Data Center market segment, for Layer-2, Layer-3, and IRB VPN services in the Service Provider market segment, and for fabric overlay and WAN connectivity in the Enterprise networks. For Data Center and Enterprise applications, there is a need to provide inter-site and WAN connectivity over public Internet in a secured manner with the same level of privacy, integrity, and authentication for tenant's traffic as used in IPsec tunneling using IKEv2. This document presents a solution where BGP point-to-multipoint signaling is leveraged for key and policy exchange among PE devices to create private pair-wise IPsec Security Associations without IKEv2 point-to- point signaling or any other direct peer-to-peer session establishment messages. EVPN uses BGP as control-plane protocol for distribution of information needed for discovery of PEs participating in a VPN, discovery of PEs participating in a redundancy group, customer MAC addresses and IP prefixes/addresses, aliasing information, tunnel encapsulation types, multicast tunnel types, multicast group memberships, and other info. The advantages of using BGP control plane in EVPN are well understood including the following: 1) A full mesh of BGP sessions among PE devices can be avoided by using Route Reflector (RR) where a PE only needs to setup a single BGP session between itself and the RR as opposed to setting up N BGP sessions to N other remote PEs; therefore, reducing number of BGP sessions from O(N^2) to O(N) in the network. Furthermore, RR hierarchy can be leveraged to scale the number of BGP routes on the RR. 2) MP-BGP route filtering and constrained route distribution can be leveraged to ensure that the control-plane traffic for a given VPN is only distributed to the PEs participating in that VPN. For setting up point-to-point security association (i.e., IPsec tunnel) between a pair of EVPN PEs, it is important to leverage BGP point-to-multipoint singling architecture using the RR along with its route filtering and constrain mechanisms to achieve the performance and the scale needed for large number of security associations (IPsec tunnels) along with their frequent re-keying requirements. Using BGP signaling along with the RR (instead of peer-to-peer protocol such as IKEv2) reduces number of message exchanges needed for SAs establishment and maintenance from O(N^2) to O(N) in the network. be increased from O(N) to O(N^2). Sajassi et al. Expires May 20, 2019 [Page 6] INTERNET DRAFT Secure EVPN October 20, 2018 2 Requirements The requirements for secured EVPN are captured in the following subsections. 2.1 Tenant's Layer-2 and Layer-3 data & control traffic Tenant's layer-2 and layer-3 data and control traffic SHALL be protected by IPsec cryptographic methods. This implies not only tenant's data traffic SHALL be protected by IPsec but also tenant's control and routing information that are advertised in BGP SHALL also be protected by IPsec. This in turn implies that BGP session SHALL be protected by IPsec. 2.2 Tenant's Unicast & Multicast Data Protection Tenant's layer-2 and layer-3 unicast traffic SHALL be protected by IPsec. In addition to that, tenant's layer-2 broadcast, unknown unicast, and multicast traffic as well as tenant's layer-3 multicast traffic SHALL be protected by IPsec when ingress replication or assisted replication are used. The use of BGP P2MP signaling for setting up P2MP SAs in P2MP multicast tunnels is for future study. 2.3 P2MP Signaling for SA setup and Maintenance BGP P2MP signaling SHALL be used for IPsec SAs setup and maintenance. The BGP signaling SHALL follow P2MP signaling framework per [CONTROLLER-IKE] for IPsec SAs setup and maintenance in order to reduce the number of message exchanges from O(N^2) to O(N) among the participant PE devices. 2.3 Granularity of Security Association Tunnels The solution SHALL support the setup and maintenance of IPsec SAs at the following level of granularities: 1) Per pair of PEs: A single IPsec tunnel between a pair of PEs to be used for all tenants' traffic supported by the pair of PEs. 2) Per tenant: A single IPsec tunnel per tenant per pair of PEs. For example, if there are 1000 tenants supported on a pair of PEs, then 1000 IPsec tunnels are required between that pair of PEs. 3) Per subnet: A single IPsec tunnel per subnet (e.g., per VLAN/EVI) of a tenant on a pair of PEs. 4) Per pair of IP addresses: A single IPsec tunnel per pair of IP addresses of a tenant on a pair of PEs. Sajassi et al. Expires May 20, 2019 [Page 7] INTERNET DRAFT Secure EVPN October 20, 2018 5) Per pair of MAC addresses: A single IPsec tunnel per pair of MAC addresses of a tenant on a pair of PEs. 2.4 Support for Policy and DH-Group List The solution SHALL support a single policy and DH group for all SAs as well as supporting multiple policies and DH groups among the SAs. 3 Solution Description This solution uses BGP P2MP signaling where an originating PE only send a message to Route Reflector (RR) and then the RR reflects that message to the interested recipient PEs. The framework for such signaling is described in [CONTROLLER-IKE] and it is referred to as device-to-controller trust model. This trust model is significantly different than the traditional peer-to-peer trust model where a P2P signaling protocol such as IKEv2 [RFC7296] is used in which the PE devices directly authenticate each other and agree upon security policy and keying material to protect communications between themselves. The device-to-controller trust model leverages P2MP signaling via the controller (e.g., the RR) to achieve much better scale and performance for establishment and maintenance of large number of pairwise Security Associations (SAs) among the PEs. This device-to-controller trust model first secures the control channel between each device and the controller using peer-to-peer protocol such as IKEv2 [RFC7296] to establish P2P SAs between each PE and the RR. It then uses this secured control channel for P2MP signaling in establishment of P2P SAs between a pair of PE devices. Each PE advertised to other PEs via the RR the information needed in establishment of pair-wise SAs between itself an every other remote PEs. These pieces of information are sent as Sub-TLVs of IPSec tunnel type in BGP Tunnel Encapsulation attribute. These Sub-TLVs are detailed in section 5 and they are based on IKEv2 specification [RFC7296]. The IPsec tunnel TLVs along with its Sub-TLVs are sent along with the BGP route (NLRI) for a given level of granularity. If only a single SA is required per pair of PE devices to multiplex user traffic for all tenants, then IPsec tunnel TLV is advertised along with IPv4 or IPv6 NLRI representing loopback address of the originating PE. It should be noted that this is not a VPN route but rather an IPv4 or IPv6 route. If a SA is required per tenant between a pair of PE devices, then IPsec tunnel TLV can be advertised along with EVPN IMET route Sajassi et al. Expires May 20, 2019 [Page 8] INTERNET DRAFT Secure EVPN October 20, 2018 representing the tenant or can be advertised along with a new EVPN route representing the tenant. If a SA is required per tenant's subnet (e.g., per VLAN) between a pair of PE devices, then IPsec tunnel TLV is advertised along with EVPN IMET route. If a SA is required between a pair of tenant's devices represented by a pair of IP addresses, then IPsec tunnel TLV is advertised along with EVPN IP Prefix Advertisement Route or EVPN MAC/IP Advertisement route. If a SA is required between a pair of tenant's devices represented by a pair of MAC addresses, then IPsec tunnel TLV is advertised along with EVPN MAC/IP Advertisement route. If a SA is required between a pair of tenant's devices represented by a VLAN or a port, then IPsec tunnel TLV is advertised along with EVPN Ethernet AD route. 3.1 Distribution of Public Keys and Policies One of the requirements for this solution is to support a single DH group and a single policy for all SAs as well as to support multiple DH groups and policies among the SAs. The following subsections describe what pieces of information (what Sub-TLVs) are needed to be exchanged to support a single DH group and a single policy versus multiple DH groups and multiple policies. 3.1.1 Minimum Set For SA establishment, at the minimum, a PE needs to advertise to other PEs, its ID, a notification to indicate if this is its initial contact, key exchange including DH public number and DH group, and Nonce. When a single policy is used among all SAs, it is assumed that this single policy is configured by the management system in all the PE devices and thus there is no need to signal it. The information that need to be signaled (using RFC7296 notations) are: ID, [N(INITIAL_CONTACT),] KE, Ni; where ID payload is defined in section 3.5 of [RFC7296] N (Notify) Payload in section 3.10 of [RFC7296] KE (Key Exchange) payload in section 3.4 of [RFC7296] Ni (Nonce) payload in section 3.9 of [RFC7296] KE payload contains the DH public number and also identifies which DH Sajassi et al. Expires May 20, 2019 [Page 9] INTERNET DRAFT Secure EVPN October 20, 2018 group to use. ID sub-TLV would not be needed in BGP because tunnel attribute already carries originator ID. Section 5 details these sub- TLVs as part of IPsec tunnel TLV in BGP Tunnel Encapsulation Attribute. 3.1.2 Single Policy If a single policy needs to be signaled among per tenant or per subnet among a set of PEs, then in addition to the information described in section 3.1.1, Security Association sub-TLV needs to be signaled as well. The payload for this sub-TLV is defined in section 3.3 of [RFC7296] and detailed in section 5.3. ID, [N(INITIAL_CONTACT),SA, KE, Ni SA (Security Association) payload in section 3.3 of [RFC7296] A single SA payload identifies a single IPsec policy. One important restriction on the SA Payload is that an standard IKE SA payload can contain multiple transform; however, [CONTROLLER-IKE] restricts the SA payload to only a single transform for each transform type as described in section A.3.1 of [CONTROLLER-IKE]. 3.1.3 Policy-list & DH-group-list There can be scenarios for which there is a need to have multiple policy options. This can happen when there is a need for policy change and smooth migration among all PE devices to the new policy is required. It can also happen if different PE devices have different capabilities within the network. In these scenairos, PE devices need to be able to choose the correct policy to use for each other. This multi-policy scheme is described in section 6 of [CONTROLLER-IKE]. In order to support this multi-policy feature, a PE device MUST distribute a policy list. This list consists of multiple distinct policies in order of preference, where the first policy is the most preferred one. The receiving PE selects the policy by taking the received list (starting with the first policy) and comparing that against its own list and choosing the first one found in common. If there is no match, this indicates a configuration error and the PEs MUST NOT establish new SAs until a message is received that does produce a match. Furthermore, when a device supports more than one DH group, then a unique DH public number MUST be specified for each in order of preference. The selection of which DH group to use follows the same logic as Policy selection, using the receiver's list order until a Sajassi et al. Expires May 20, 2019 [Page 10] INTERNET DRAFT Secure EVPN October 20, 2018 match is found in the initiator's list. In order to support multi-policy a policy list is signaled in addition to the information described in section 3.1.1. Furthermore, in order to support multi-DH-groups, a DH group list along with its nonce list are signaled instead of a single DH group and a single nonce as described in section 3.1.1. ID, [N(INITIAL_CONTACT), [SA], [KE], [Ni] [SA] list of IPsec policies (i.e., list of SA payloads) [KE] list of KE payloads 3.2 Initial IPsec SAs Generation The procedure for generation of initial IPsec SAs is described in section 3 of [CONTROLLER-IKE]. This section gives a summary of it in context of BGP signaling. When a PE device first comes up and wants to setup an IPsec SA between itself and each of the interested remote PEs, it generates a DH pair along for each of its intended IPsec SA using an algorithm defined in the IKEv2 Diffie-Hellman Group Transform IDs [IKEv2-IANA]. The originating PE distributes DH public value along with a nonce (using IPsec Tunnel TLV in Tunnel Encapsulation Attribute) to other remote PEs via the RR. Each receiving PE uses this DH public number and the corresponding nonce in creation of IPsec SA pair to the originating PE - i.e., an outbound SA and an inbound SA. The detail procedures are described in section 5.2 of [CONTROLLER-IKE]. 3.3 Re-Keying A PE can initiate re-keying at any time due to local time or volume based policy or due to the result of cipher counter nearing its final value. The rekey process is performed individually for each remote PE. If rekeying is performed with multiple PEs simultaneously, then the decision process and rules described in this rekey are performed independently for each PE. Section 4 of [CONTROLLER-IKE] describes this rekeying process in details and gives examples for a single IPsec device (e.g., a single PE) rekey versus multiple PE devices rekey simultaneously. 3.4 IPsec Databases The Peer Authorization Database (PAD), the Security Policy Database (SPD), and the Security Association Database (SAD) all need to be Sajassi et al. Expires May 20, 2019 [Page 11] INTERNET DRAFT Secure EVPN October 20, 2018 setup as defined in the IPsec Security Architecture [RFC4301]. Section 5 of [CONTROLLER-IKE] gives a summary description of how these databases are setup for the controller-based model where key is exchanged via P2MP signaling via the controller (e.g., the RR) and the policy can be either signaled via the RR (in case of multiple policies) or configured by the management station (in case of single policy). 4 Encapsulation Vast majority of Encapsulation for Network Virtualization Overlay (NVO) networks in deployment are based on UDP/IP with UDP destination port ID indicating the type of NVO encapsulation (e.g., VxLAN, GPE, GENEVE, GUE) and UDP source port ID representing flow entropy for load-balancing of the traffic within the fabric based on n-tuple that includes UDP header. When encrypting NVO encapsulated packets using IP Encapsulating Security Payload (ESP), the following two options can be used: a) adding a UDP header before ESP header (e.g., UDP header in clear) and b) no UDP header before ESP header (e.g., standard ESP encapsulation). The following subsection describe these encapsulation in further details. 4.1 Standard ESP Encapsulation When standard IP Encapsulating Security Payload (ESP) is used (without outer UDP header) for encryption of NVO packets, it is used in transport mode as depicted below. When such encapsulation is used, the Tunnel Type of Tunnel Encapsulation TLV is set to ESP-Transport and the Tunnel Type of Encapsulation Extended Community is set to NVO encapsulation type (e.g., VxLAN, GENEVE, GPE, etc.). This implies that the customer packets are first encapsulated using NVO encapsulation type and then it is further encapsulated & encrypted using ESP-Transport mode. Sajassi et al. Expires May 20, 2019 [Page 12] INTERNET DRAFT Secure EVPN October 20, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Header | | MAC Header | +-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+ | Eth Type = IPv4/IPv6 | | Eth Type = IPv4/IPv6 | +-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+ | IP Header | | IP Header | | Protocol = UDP | | Protocol = ESP | +-----------------------+ +-----------------------+ | UDP Header | | ESP Header | | Dest Port = VxLAN | +-----------------------+ +-----------------------+ | UDP Header | | VxLAN Header | | Dest Port = VxLAN | +-----------------------+ +-----------------------+ | Inner MAC Header | | VxLAN Header | +-----------------------+ +-----------------------+ | Inner Eth Payload | | Inner MAC Header | +-----------------------+ +-----------------------+ | CRC | | Inner Eth Payload | +-----------------------+ +-----------------------+ | ESP Trailer (NP=UDP) | +-----------------------+ | CRC | +-----------------------+ Figure 3: VxLAN Encapsulation within ESP 4.2 ESP Encapsulation within UDP packet In scenarios where NAT traversal is required ([RFC3948]) or where load balancing using UDP header is required, then ESP encapsulation within UDP packet as depicted in the following figure is used. The ESP for NVO applications is in transport mode. The outer UDP header (before the ESP header) has its source port set to flow entropy and its destination port set to 4500 (indicating ESP header follows). A non-zero SPI value in ESP header implies that this is a data packet (i.e., it is not an IKE packet). The Next Protocol field in the ESP trailer indicates what follows the ESP header, is a UDP header. This inner UDP header has a destination port ID that identifies NVO encapsulation type (e.g., VxLAN). Optimization of this packet format where only a single UDP header is used (only the outer UDP header) is for future study. When such encapsulation is used, the Tunnel Type of Tunnel Encapsulation TLV is set to ESP-in-UDP-Transport and the Tunnel Type of Encapsulation Extended Community is set to NVO encapsulation type Sajassi et al. Expires May 20, 2019 [Page 13] INTERNET DRAFT Secure EVPN October 20, 2018 (e.g., VxLAN, GENEVE, GPE, etc.). This implies that the customer packets are first encapsulated using NVO encapsulation type and then it is further encapsulated & encrypted using ESP-in-UDP with Transport mode. [RFC3948] +-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Header | | MAC Header | +-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+ | Eth Type = IPv4/IPv6 | | Eth Type = IPv4/IPv6 | +-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+ | IP Header | | IP Header | | Protocol = UDP | | Protocol = UDP | +-----------------------+ +-----------------------+ | UDP Header | | UDP Header | | Dest Port = VxLAN | | Dest Port = 4500(ESP) | +-----------------------+ +-----------------------+ | VxLAN Header | | ESP Header | +-----------------------+ +-----------------------+ | Inner MAC Header | | UDP Header | +-----------------------+ | Dest Port = VxLAN | | Inner Eth Payload | +-----------------------+ +-----------------------+ | VxLAN Header | | CRC | +-----------------------+ +-----------------------+ | Inner MAC Header | +-----------------------+ | Inner Eth Payload | +-----------------------+ | ESP Trailer (NP=UDP) | +-----------------------+ | CRC | +-----------------------+ Figure 4: VxLAN Encapsulation within ESP Within UDP 5 BGP Encoding This document defines two new Tunnel Types along with its associated sub-TLVs for The Tunnel Encapsulation Attribute [TUNNEL-ENCAP]. These tunnel types correspond to ESP-Transport and ESP-in-UDP-Transport as described in section 4. The following sub-TLVs apply to both tunnel types unless stated otherwise. 5.1 ESP Notify Sub-TLV Sajassi et al. Expires May 20, 2019 [Page 14] INTERNET DRAFT Secure EVPN October 20, 2018 This sub-TLV corresponds to Notify payload of IPsec Encapsulation Security Payload protocol as defined in IKEv2 [RFC7296]. This payload is defined and described in section 3.10 of [RFC7296]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Payload |C| Reserved | Payload Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol ID | SPI Size | Notify Message Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Security Parameter Index (SPI) ~ | | +---------------------------------------------------------------+ | | ~ Notification Data ~ | | +---------------------------------------------------------------+ Figure 5: Notify Payload Format 5.2 ESP Key Exchange Sub-TLV This sub-TLV corresponds to Key Exchange payload of IPsec Encapsulation Security Payload protocol as defined in IKEv2 [RFC7296]. This payload is defined and described in section 3.4 of [RFC7296]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Payload |C| Reserved | Payload Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Diffie-Hellman Group Number | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Key Exchange Data ~ | | +---------------------------------------------------------------+ Figure 6: Key Exchange Payload Format 5.3 ESP Nonce Sub-TLV This sub-TLV corresponds to Nonce payload of IPsec Encapsulation Sajassi et al. Expires May 20, 2019 [Page 15] INTERNET DRAFT Secure EVPN October 20, 2018 Security Payload protocol as defined in IKEv2 [RFC7296]. This payload is defined and described in section 3.9 of [RFC7296]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Payload |C| Reserved | Payload Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Nonce Data ~ | | +---------------------------------------------------------------+ Figure 7: Nonce Payload Format 5.3 ESP Proposals Sub-TLV This sub-TLV corresponds to Proposal payload of IPsec Encapsulation Security Payload protocol as defined in IKEv2 [RFC7296]. This payload is defined and described in section 3.3 of [RFC7296]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Payload |C| Reserved | Payload Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ ~ | | +---------------------------------------------------------------+ Figure 8: Security Association Payload Proposals (Variable) - one or more proposal substructures Sajassi et al. Expires May 20, 2019 [Page 16] INTERNET DRAFT Secure EVPN October 20, 2018 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Last Substruc | Reserved | Proposal Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Proposal Num | Protocol ID | SPI Size | Num Transforms| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ SPI (Variable) ~ | | +---------------------------------------------------------------+ | | ~ ~ | | +---------------------------------------------------------------+ Figure 9: Proposal Substructure 6 Applicability to other VPN types Although P2MP BGP signaling for establishment and maintenance of SAs among PE devices is described in this document in context of EVPN, there is no reason why it cannot be extended to other VPN technologies such as IP-VPN [RFC4364], VPLS [RFC4761] & [RFC4762], and MVPN [RFC6513] & [RFC6514] with ingress replication. The reason EVPN has been chosen is because of its pervasiveness in DC, SP, and Enterprise applications and because of its ability to support SA establishment at different granularity levels such as: per PE, Per tenant, per subnet, per Ethernet Segment, per IP address, and per MAC. For other VPN technology types, a much smaller granularity levels can be supported. For example for VPLS, only the granularity of per PE and per subnet can be supported. For per-PE granularity level, the mechanism is the same among all the VPN technologies as IPsec tunnel type (and its associated TLV and sub-TLVs) are sent along with the PE's loopback IPv4 (or IPv6) address. For VPLS, if per-subnet (per bridge domain) granularity level needs to be supported, then the IPsec tunnel type and TLV are sent along with VPLS AD route. The following table lists what level of granularity can be supported by a given VPN technology and with what BGP route. Sajassi et al. Expires May 20, 2019 [Page 17] INTERNET DRAFT Secure EVPN October 20, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Functionality | EVPN | IP-VPN | MVPN | VPLS | +---------------+-------------+-------------+-----------+---------+ | per PE |IPv4/v6 route|IPv4/v6 route|IPv4/v6 rte|IPv4/v6 | +---------------+-------------+-------------+-----------+---------+ | per tenant |IMET (or new)|lpbk (or new)| I-PMSI | N/A | +---------------+-------------+-------------+-----------+---------+ | per subnet | IMET | N/A | N/A | VPLS AD | +---------------+-------------+-------------+-----------+---------+ | per IP |EVPN RT2/RT5 | VPN IP rt | *,G or S,G| N/A | +---------------+-------------+-------------+-----------+---------+ | per MAC | EVPN RT2 | N/A | N/A | N/A | +---------------+-------------+-------------+-----------+---------+ 7 Acknowledgements 8 Security Considerations 9 IANA Considerations A new transitive extended community Type of 0x06 and Sub-Type of TBD for EVPN Attachment Circuit Extended Community needs to be allocated by IANA. 10 References 10.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017. [RFC7432] Sajassi et al., "BGP MPLS Based Ethernet VPN", RFC 7432, February, 2015. [RFC8365] Sajassi et al., "A Network Virtualization Overlay Solution Sajassi et al. Expires May 20, 2019 [Page 18] INTERNET DRAFT Secure EVPN October 20, 2018 Using Ethernet VPN (EVPN)", RFC 8365, March, 2018. [TUNNEL-ENCAP] Rosen et al., "The BGP Tunnel Encapsulation Attribute", draft-ietf-idr-tunnel-encaps-03, November 2016. [CONTROLLER-IKE] Carrel et al., "IPsec Key Exchange using a Controller", draft-carrel-ipsecme-controller-ike-00, July, 2018. [RFC3948] Huttunen et al., "UDP Encapsulation of IPsec ESP Packets", RFC 3948, January 2005. [IKEV2-IANA] IANA, "Internet Key Exchange Version 2 (IKEv2) Parameters", February 2016, www.iana.org/assignments/ikev2-parameters/ikev2- parameters.xhtml. [RFC4301] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, December 2005. 10.2 Informative References [RFC4364] Rosen, E., et. al., "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, February 2006. [RFC4761] Kompella, K., et. al., "Virtual Private LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling", RFC 4761, January 2007. [RFC4762] Kompella, K., et. al., "Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling", RFC 4762, January 2007. [RFC6513] Rosen, E., et. al., "Multicast in MPLS/BGP IP VPNs", RFC 6513, February 2012. [RFC6514] Rosen, E., et. al., "BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNs", RFC 6514, February 2012. [RFC7606] Chen, E., Scudder, J., Mohapatra, P., and K. Patel, "Revised Error Handling for BGP UPDATE Messages", RFC 7606, August 2015, . [802.1Q] "IEEE Standard for Local and metropolitan area networks - Media Access Control (MAC) Bridges and Virtual Bridged Local Area Networks", IEEE Std 802.1Q(tm), 2014 Edition, November 2014. Sajassi et al. Expires May 20, 2019 [Page 19] INTERNET DRAFT Secure EVPN October 20, 2018 [RFC7348] Mahalingam, M., et al., "Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014. [GENEVE] Gross, J., et al., "Geneve: Generic Network Virtualization Encapsulation", Work in Progress, draft-ietf-nvo3-geneve-06, March 2018. Authors' Addresses Ali Sajassi Cisco Email: sajassi@cisco.com Ayan Banerjee Cisco Email: ayabaner@cisco.com Samir Thoria Cisco Email: sthoria@cisco.com David Carrel Cisco Email: carrel@cisco.com Brian Weis Cisco Email: bew@cisco.com Sajassi et al. Expires May 20, 2019 [Page 20]